This is a note to let you know that I've just added the patch titled
cpufreq: armada-37xx: forbid cpufreq for 1.2 GHz variant
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
cpufreq-armada-37xx-forbid-cpufreq-for-1.2-ghz-varia.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit c78c895f3773d925a51bbe89e33799e27293a6c0
Author: Marek Behún <kabel@xxxxxxxxxx>
Date: Thu Jul 1 00:56:01 2021 +0200
cpufreq: armada-37xx: forbid cpufreq for 1.2 GHz variant
[ Upstream commit 484f2b7c61b9ae58cc00c5127bcbcd9177af8dfe ]
The 1.2 GHz variant of the Armada 3720 SOC is unstable with DVFS: when
the SOC boots, the WTMI firmware sets clocks and AVS values that work
correctly with 1.2 GHz CPU frequency, but random crashes occur once
cpufreq driver starts scaling.
We do not know currently what is the reason:
- it may be that the voltage value for L0 for 1.2 GHz variant provided
by the vendor in the OTP is simply incorrect when scaling is used,
- it may be that some delay is needed somewhere,
- it may be something else.
The most sane solution now seems to be to simply forbid the cpufreq
driver on 1.2 GHz variant.
Signed-off-by: Marek Behún <kabel@xxxxxxxxxx>
Fixes: 92ce45fb875d ("cpufreq: Add DVFS support for Armada 37xx")
Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/cpufreq/armada-37xx-cpufreq.c b/drivers/cpufreq/armada-37xx-cpufreq.c
index e4782f562e7a..2de7fd18f66a 100644
--- a/drivers/cpufreq/armada-37xx-cpufreq.c
+++ b/drivers/cpufreq/armada-37xx-cpufreq.c
@@ -102,7 +102,11 @@ struct armada_37xx_dvfs {
};
static struct armada_37xx_dvfs armada_37xx_dvfs[] = {
- {.cpu_freq_max = 1200*1000*1000, .divider = {1, 2, 4, 6} },
+ /*
+ * The cpufreq scaling for 1.2 GHz variant of the SOC is currently
+ * unstable because we do not know how to configure it properly.
+ */
+ /* {.cpu_freq_max = 1200*1000*1000, .divider = {1, 2, 4, 6} }, */
{.cpu_freq_max = 1000*1000*1000, .divider = {1, 2, 4, 5} },
{.cpu_freq_max = 800*1000*1000, .divider = {1, 2, 3, 4} },
{.cpu_freq_max = 600*1000*1000, .divider = {2, 4, 5, 6} },
